Extensible boom structure



March 3, 1970 w. M. PIERCE,.JR 3,

I EXTENSIBLE .BOOM STRUCTURE Filed May 27, 1968 4 Sheets-Sheet 1 1 N VEN TOR.

Maw: ves l/Q. BY

March 1970 w. M. PIERCE, JR 3,493,474

EXTENSIBLE ,BOOM STRUCTURE Filed May 27, 1968 4 Sheets-Sheet 2 INVENTOR. A/wA s M- fQsQdj k. BY

March 3, 1970 w. M. PIERCE, JR 3, I

EXTENSIBLE BOOM STRUCTURE Filed May 27, 1968 v 4 Sheets-Sheet 5 (\j, to BY v March 3,1970 w. M. PIERCE, JR 3,493,474

, EXTENSIBLE BOOM STRUCTURE Filed May 27, 1968 4 Sheets-Sheet 4 INVENTOR. Mir/v5 f2 fiE/PCtj we I6 BY M4, JMY

A TWP/V 25 United States Patent U.S. Cl. 212-59 2 Claims ABSTRACT OF THE DISCLOSURE A boom structure capable of reaching into locations above, on a level with or below the support on which the boom is mounted is provided by a support mounted on a base structure, the support capable of being rotated in a horizontal plane. A first arm capable of being raised and lowered is articulately joined to the support. A second arm is articulately joined to the first arm so as to be capable of being moved vertically or horizontally with respect to the first arm. A third arm is articulately joined to the second arm so as to be capable of being moved vertically with respect to the second arm. A bucket i supported at the end of the third arm to pivot with respect to the third arm.

Articulated boom structures, usually mounted on trucks, of the type that raise and support an individual a distance away from the truck have been found useful for many purposes. For example, they have been employed in the construction and maintenance of overhead electrical lines and allied equipment, street lights, cutting of tree limbs, etc.

It is an object of the present invention to provide a boom structure which is capable of being maneuvered into areas located above, below and level with the base of the boom.

Another object is to provide a boom structure which will reach all areas located above and below the base of the boom, and have a minimum number of operating parts.

A further object is to provide the end of the boom with a curved structure which gives the boom particularly broad access features.

Still another object is to provide a boom to which a bucket for carrying a workman is suspended at the end of the boom.

Yet another object is to provide means for situating the boom upon a motor vehicle for purposes of transporting the boom to desired destinations.

A still further object is to provide a boom construction mounted on a motor vehicle and capable of being stowed so that it may be transported or stored in a compact manner.

These and other objects of the present invention will be apparent from the following description.

In accordance with the present invention, there is provided an extensible boom structure comprising a support mounted on a base structure and capable of being rotated in a horizontal plane, a first arm articulately joined to the support, and capable of being raised and lowered, a second arm articulately joined to the first arm, and capable of vertical and horizontal movement relative to the first arm, and a third arm articulately joined to the second arm, and capable of vertical movement relative to the second arm.

The invention includes such a boom structure wherein a bucket is attached to the end of the third arm. The invention includes such a boom structure wherein the bucket is maintained in alignment with respect to the vertical.

The invention includes such a boom structure wherein ice a fourth arm is articulately joined to the third arm. A bucket attached to the fourth arm is maintained in alignment with respect to the vertical.

The invention includes such a boom structure wherein the second arm is joined to the first arm by means comprising a member which is maintained in a position substantially parallel to the base of the support. The parallel position is maintained by means joining the support and the means joining the second arm to the first arm.

The invention includes such a boom structure wherein the second arm is joined to the first arm by means comprising a member for rotating the second arm in a horizontal plane.

The invention includes such a boom structure wherein vertical movement of each arm is effected by piston means. i The present invention provides a boom structure wherein the boom is capable of reaching those areas which are located between the limits ranging from above to below the base of the boom. The locations to be reached above and below the base of the boom are limited only by the dimensions or length of the boom structure. The bucket is vertically oriented regardless of the position or direction of the boom. This vertical orientation is accomplished in an automatic manner by the bucket itself.

FIG. 1 is a side view of the boom of the present invention mounted upon a truck.

FIG. 2 is a plan view of FIG. 1.

FIG. 3 is a front elevation showing the boom extended and the various articulations thereof.

FIG. 4 is a plan view showing the horizontal articulations of the-outer arms relative to the first arm of the boom.

FIG. 5 is a side view similar to FIG. 1 but showing the bucket mounted on a fourth articulated arm,

FIG. 6 is a side view showing the means for maintaining the bucket in vertical alignment.

The boom structure when mounted on a motor vehicle, truck, tractor or trailer, is shown in FIGURES 1 and 2. The vehicle 10 includes a post 11 which allows for storage of the boom. The features making possible stowage of the boom are important for transporting the boom along congested roadways or other areas where space is at a premium. Stowage of the boom also allows the storage space required for the boom to be at a minimum.

The boom has three arms 12, 13 and 14. A bucket 15 is attached to the outer end of arm 14 by means of bearing 39. As shown, arm 14 is attached to arm 13 which in turn is attached to arm 12. Arm 12 is attached to supporting member 16 which is mounted on rotatable platform 17. A series of weights are attached to support membe 16 to counter the weight of the boom. Spring locks (not shown) on all four wheels of the vehicle lock the axles to the frame. An interlock (not shown) on the platform 17 prohibits rotation until the spring locks are engaged, and prevents disengaging of the spring locks until platform 17 is at stowed position. Rotation of platform 17 enables support member 16 and arm 12 to be moved to any desired position in the horizontal plane. An auxiliary engine 19 may be mounted on one side of support member 16.

As shown in FIGURE 3, arm 12 is mounted on shaft 20. Arm 12 is attached to piston 21 at joint 20a. The piston is mounted in cylinder 22 within support member 16. Movement of piston 21 into and out of the cylinder serves to raise or lower arm 12. Arm 12 therefore has freedom of motion in the vertical plane as well as in the horizontal plane.

Arm 12 is joined to arm 13 through plate 23, rotary member 24 and supporting plate 25. Plate 23 has a projection 23a, one end of which is rotatably mounted on axle 26. The other end of projection 23a is connected by pivot 27 to one end of linking rod 28. At its other end, rod 28 is connected to support 16 by pivot 29. It will be seen that rod and vertical movement of arm 12 acts on rod 28 in such a way that plate 23 is always maintained in a horizontal plane.

Rotary member 24 is mounted on vertical shaft 36 disposed in the center of plate 23. Member 24 is rotated by a worm gear (not shown), or other suitable means, driven by motor 31. Plate 25 is attached to the underside of rotary member 24. Arm 13 is mounted on axle 32 journalled through the lower portion of plate 25. Rotation of member 24 enables arm 13 to be moved to any desired position in the horizontal plane. Arm 13 and plate 25 are connected by a piston 33 and cylinder 34 mounted on shafts 35 and 36. Movement of piston 33 into and out of cylinder 34 serves to control vertical movement of arm 13. Arm 13 therefore has freedom of movement in the vertical plane as well as in the horizontal plane.

The vertical movement of arm 14 is controlled by means of piston 37 and cylinder 38. The cylinder is mounted on arm 13, and the piston is connected to arm 14.

Some of the numerous positions in which it is possible to locate the bucket are shown by the broken lines in FIGURE 3, thus demonstrating the outstanding versatility of the boom construction of the present invention.

FIGURE 4 shows the horizontal movement of arm 13 relative to arm 12 that is made possible by the boom construction of the present invention. Again this demonstrates the outstanding versatility made possible by the boom construction of the present invention. As also shown in FIGURE 4, more than one piston and cylinder arrangement may be employed to control the vertical movement of arm 13. In the drawing cylinder 34 and piston 35 are supplemented by cylinder 34a and piston 35a.

FIGURE shows bucket attached to arm 44 by means of bearing 39. Arm 44 may be articulated similarly to arm 14 and its articulation may be controlled by means of a piston 43 and cylinder 42, or arm 44 may be fixed. The bucket is intended to hold personnel or workmen, and may be constructed so as to accommodate one or more persons. As shown in FIGURE 6, the bucket is supported in a manner which assures that its vertical orientation will remain constant. In this way the end of the boom can assume any position whatsoever, and the bucket will be always vertically oriented. Such vertical orientation of the bucket is desirable for the safety and comfort of the person or persons supported therein. To this end a rod 50 pivotally interconnects the end of arm 51 fixed to a stationary pivot shaft 52 and the outer end of arm 53 fixed to revolvable shaft 54. The levelling mechanism includes a split pulley 55 from which cables 56 and 57 pass outwardly toward the bucket. One end portion of cable '56 is wrapped around one section of split pulley 55 and anchored thereto, and one end portion of cable 57 is wrapped around the other pulley section and anchored thereto. Cables 56 and 57 are interconnected through rods 58, and 59, and cable 60.

As shown in the last-mentioned view, the rods 58, 59 which may be of substantial length and which are constructed of a material having a high dielectric strength, such as plastic reinforced with glass fibers, extend lengthwise in the boom. One rod 58 has the inner end thereof connected to the outer end of the cable 56 while the other rod 59 has the inner end thereof connected to the outer end of the cable 57. The other ends of the rods are connected to the respective ends of the cable 60 which has the central or middle portion thereof wrapped around the pulley 61 and trained over and idler 62 supported in the outer end portion of the boom adjacent the enlarge ment 63. The cable 60 has the middle part of the portion thereof wrapped around the pulley 61 anchored to the latter, as at 64, to resist slippage of the cable on the pulley under normal operating conditions.

The operation of the levelling mechanism will be manifest from the foregoing disclosure. When the lower boom section is at rest, as in the position shown in FIG- URE 6, for example, and the upper boom section is raised, the rod 50, interconnecting the arms 52 and 53 tends to maintain the pulley in stationary relation to the lower boom section, and as the upper boom section is raised from the position of FIG. 6, that is, swung in a clockwise direction as viewed here, the cable 56 is unlaid from the pulley 55, while the cable 57 is laid on the lastmentioned pulley, and through movement of the cables 56 and 57, Which control the rods 58 and 59 and the cable 60, the bucket-line work platform is maintained in upright position. It will be understood that the cable 56 is laid and the cable 57 is unlaid when the upper boom section is lowered. When the lower boom section is raised, the pulley 55 is rotated in a clockwise direction, as viewed in FIGURE 6, through the link-controlled arm 51. This movement of the pulley 55 relatively to the lower boom tends to maintain the bucket-like work platform in upright position, and it will be understood from the foregoing that when the lower boom section is lowered, the pulley 55 is rotated relatively to the lower boom in opposite direction to maintain the platform in upright position. Should the cable slip on the pulley 61, or should either of the cables 56 or 57 become slack, the sections of the split pulley 55 may be adjusted angularly to one another. This adjustment may be made to compensate for slippage of the cable 60 or to remove slack from the cables 56 and 57.

Controls may be mounted in the bracket to permit a workman therein to control all motions and operations. Additional controls may be located, if desired, at any other convenient locations.

It will be understood that the foregoing description with the details of exemplary structure is not to be construed in any way to limit the invention, but that modifications may be made thereto without departing from the scope of the invention as set forth in the following claims.

What is claimed is:

1. An extensible boom structure adapted to reach locations below the support on which the boom is mounted and in addition is adapted to reach locations above and level with the support including: a vehicle adapted for mounting said boom structure thereon, a horizontally rotatable support mounted on said vehicle, a first arm articulately mounted on said support and adapted to be raised and lowered relative to said support, articulating means joining said first arm to a second arm, said articulating means allowing said second arm to articulate both horizontally and vertically relative to said first arm and having a rotary member connected to said first arm by connecting means adapted to maintain said rotary member in a horizontal plane, said second arm being articulately connected to said rotary member adjacent the underside of said rotary member, and piston and cylinder means for vertical articulation of said second arm having one end connected to said rotary member above said connec tion of said second arm to said rotary member and having the other end connected to said second arm, and a third arm articulately connected to said second arm, and piston and cylinder means for vertical articulation of said third arm.

2. The extensible boom structure of claim 1 wherein said articulating means joining said first arm to said second arm allowing said second arm to articulate both horizontally and vertically relative to said first arm includes a plate connected on one side of said rotary member, said plate having a projection with one end rotatably mounted on an axle connected to said first arm, the other end of said projection being connected by a pivot to one end of a linking rod pivotally connected at its opposite end to said support, said rotary member having a second plate attached to the underside thereof with a journalled References Cited UNITED STATES PATENTS 3,103,257 9/1963 Richards 182-2 6 3,132,718 5/1964 Pierce 1822 3,262,517 7/1966 Malec l822 3,357,517 12/1967 Wagner 182-2 5 REINALDO P. MACHADO, Primary Examiner US. Cl. X.R. 

